Link under macOS - Install with Packages (Beginner) is broken

[AllisonXUPR]

Under Option A: Local Installation - GDAL, GEOS, and PROJ.4 - macOS Install with Packages (Beginner) setup page, the last link instructions for installing programs from unidentified developers is not available.
Here is one possible alternative link to replace the original one:
Open a Mac app from an unidentified developer

[jsta]

Thanks @AllisonXUPR! Would you be willing to open a Pull Request?